Current polyethylene terephthalate (PET) containers typically are clear or uniformly shaded with minimum amount of color (color-pigments, effects pigments, dyes, or the like). One issue that has been encountered is that coloring pigments and dyes used in the manufacture of PET beverage bottles often are not recycle-friendly, e.g., inclusion of such coloring pigments and dyes in the high-value clear recycle stream is not possible. As a result, recyclers often need to collect colored containers separately and sell them at a much lower cost.
Some techniques have been developed for removing pigments and other contaminants from PET to facilitate recycling. For example, West U.S. Pat. No. 5,504,421 discloses a method of decontaminating PET by transesterifying the material to form embrittled PET, crushing the mixture and separating uncrushed material containing PET, followed by esterifying the material to form short-chain PET polymers. Such methods, which introduce considerable complexity and expense to the recycling process, are not economically feasible.
It would be desirable to make containers, such as PET beverage containers, with improved visual characteristics, especially such containers that may be subsequently recycled in existing recycling streams with no or minimal additional processing steps.